Temperature has a major influence on cardiac natriuretic peptide in salmon

Abstract

The natriuretic peptide system plays a major role in the fluid and electrolyte homeostasis in vertebrates, based on results from physiological studies (reviewed in Ruskoaho, 1992;Thibault et al. 1999) and experiments with transgenic animals (John et al. 1995;Lopez et al. 1995;Matsukawa et al. 1999). The regulation of the synthesis and secretion of cardiac A-and B-type natriuretic peptides, is, however, still incompletely understood. The ability of salmon (Salmo salar) to maintain volume and electrolyte balance despite the highly challenging osmoregulatory conditions of sea and fresh water prompted us to use it as a model for our studies on the regulation of natriuretic peptides. As an initial step, we recently cloned and sequenced from salmon heart the cDNA of a novel peptide hormone, salmon cardiac peptide (sCP) (Tervonen et al. 1998), which is stored in secretory granules and released by mechanical load, analogous to the mammalian natriuretic peptides (Kokkonen et al. 2000). Homologues of the novel peptide can be found in several teleost species . The evolutional position of fish make them ideal for studying the conserved characteristics of the natriuretic peptide system (Powers, 1989;Postlethwait et al. 1998;Wittbrot et al. 1998). They also make excellent models for studies on the general factors regulating the expression and secretion of natriuretic peptides. In keeping with this we have recently found that the promoter of the sCP gene is very active not only in salmon heart but also in mammalian cardiomyocytes, suggesting that, despite the large phylogenetic distance, the same transcription factors are responsible for the heart-specific expression of the peptides in mammals and salmon (MajalahtiPalviainen et al. 2000). Since sCP transcripts or peptide cannot be found in any tissues outside the heart (MajalahtiPalviainen et al. 2000) it can be used as a specific model for the endocrine function of the heart.In fish and other ectothermic animals, thermal balance is governed by external sources of heat, and therefore ambient temperature has a major influence on most physiological processes. Many fishes are exposed seasonally to considerable changes in water temperature. Temperature acclimation is accompanied with compensatory changes in metabolic, contractile and morphological properties of muscle, which significantly offset the negative impact of Temperature has a major influence on cardiac natriuretic peptide in salmon 1. Natriuretic peptides have a major role in fluid and electrolyte homeostasis in vertebrates. Ambient temperature has a major influence on physiological processes in ectothermic animals.Here we have studied the mechanisms of regulation of a natriuretic peptide, sCP (salmon cardiac peptide), in salmon (Salmo salar) acclimatised and acclimated to varying temperatures.2. The circulating and cardiac levels of sCP were found to be markedly upregulated in warmacclimatised and warm-acclimated salmon. The release of sCP from isolated in vitro perfused salmon ventricle was, however, not increased by ...

Steady-state effects of temperature acclimation on the transcriptome of the rainbow trout heart

“…Interestingly, in the ventricle of CA trout, the transcripts of atrial natriuretic peptide B (ANB), myosin light chain 2 and MLP were elevated by about 3-, 3-, and 5-fold, respectively, showing that cold-induced hypertrophy of the fish heart shares several markers with the hypertrophy of the mammalian heart. The increase in mRNA of ANB and its possible association with temperature-dependent increase in the relative heart mass has been recently documented in another salmonid fish (Salmo salar) (43). ANB is produced by hypertrophic ventricular myocytes, and it exerts stabilizing or moderating effect on cardiac hypertrophy.…”

The Dynamic Nature of Hypertrophic and Fibrotic Remodeling of the Fish Ventricle

“…For example, the ventricular mass of the Burmese python, Python molurus , can increase by 40% after feeding and then return to “normal” following digestion (Andersen et al, 2005 ). The hearts of many fish also show intermittent remodeling in response to seasonal temperature change with chronic cooling during winter triggering ventricular hypertrophy (Farrell et al, 1988 ; Graham and Farrell, 1989 ; Tervonen et al, 2001 ; Klaiman et al, 2011 ; Shiels et al, 2011 ). The hypertrophic trigger in this model is thought to be the increased viscosity of blood at cold (<6°C) temperatures and the hemodynamic stress of pumping this viscous blood (Graham and Farrell, 1989 ; Clark and Rodnick, 1999 ).…”

The Regulation of Troponins I, C and ANP by GATA4 and Nkx2-5 in Heart of Hibernating Thirteen-Lined Ground Squirrels, Ictidomys tridecemlineatus

“…In mouse models of dilated cardiomyopathy, ANP was found to reduce the chances of heart failure, pathological remodelling and mortality, while maintaining normal systolic function [ 60 ]. A study on salmon cardiac peptides (sCP), which are analogous to ANP and brain natriuretic peptide (BNP) in mammals, found that sCP mRNA increased at lower temperatures, coinciding with heart hypertrophy [ 61 ]. Similar to salmon, we hypothesize from our results that the hibernating thirteen-lined ground squirrel may be relying on ANP to achieve versatile regulation of heart pressure, physiology, and endocrinology.…”